This invention relates to precursors used to facilitate the deposition of a metal onto a surface, such as metal used to form conductive lines in a circuit. In particular, the invention relates to printing circuit precursors on a wide variety of substrates including flexible and non-flat substrates.
Circuit manufacturers employ numerous techniques to deposit a conductive pattern on a substrate. One technique applies a conductive seed layer to the substrate to facilitate subsequent electro/electroless plating of a metal that forms conductive lines in the conductive pattern. The conductive seed layer alone is insufficient to reliably serve as the conductive lines in a circuit, but uses large amounts of the seed material to maintain conductivity for subsequent metal addition. Another technique uses an adhesive layer to attach a conductive layer to the substrate. The adhesive layer, however, adds thickness to the final circuit, which is undesirable for circuits employed in portable and small form factor applications. Circuit manufacturers have also developed etching processes that apply a photoresist, etch the photoresist to form a pattern, add metal to form conductive lines according to the pattern, along with other process steps such as washes to cleanse byproducts from each stage. These numerous etch steps increase manufacturing complexity, add disposal requirements for etch by-products, lengthen manufacturing time, and the pattern and etch equipment raises capital cost for circuit manufacture. All these downsides burden circuit manufacturers by adding to manufacturing complexity and circuit cost.
Also, most conductive pattern manufacturing processes limit their circuits to rigid substrates. For example, a seed conductive layer needs an inflexible substrate to physically support the continuous seed layer. If the substrate bends, then the continuous and conductive seed lines crack and break, which compromises subsequent metal deposition.
The ability to manufacture a conductive pattern without these undue complexities and limitations would be desirable.